3 Point Arc

[Cableguy]

So if I understand you correctly, none of those three points is the center, rigth?

[klaus]

They all 3 lie on the circumference.

[Cableguy]

Originally Posted by klaus

They all 3 lie on the circumference.

OK, now I understand...
As Andrew usually says, just to be "pedantic", it's a matter of shoosing the correct words, as a circunference differs from a circle, exactly in its "points needed to define it"...
Its the same with a rectangle (wich assumes that all 4 angles are 90º) and a Trapezoid, wich can also be a Rectangle...

I remember now why I flawed at geometry.....

[klaus]

To be complete (pedantic):
They lie all three on the circumference of the circle.

The graphic in the word file should be clear.

Best regards

[ceaser]

Hi Klaus

Thanks for your offer to help me, but I need to know what it is going to cost me. You must bear in mind that the "CAD" module will form part of the "CEASER" program, which is a commercial software package on the market. I have users throughout Africa, Britian, China and Australia.

If you agree to this, then I will send you a list of the meaning of the buttons on the toolbars. I am busy moving everything over to panels and I will send it to you during the course of tomorrow. I have quite of lot of fieldwork that I must do today.

I am also going to work on a couple of routines during the week and towards the end of this week, I will put it on the forum again.

Thanks
Michael Papenhagen

[klaus]

Hi Micheal,

Programming has been a hobby for many years now and of course still is !
I program for my pleasure and as I wrote in a previous post the subject interests me. So I don't want to get any payment for, even it will be a comercial product.
The only point, for me, is that the program remains public to the forum members. I got many help on this forum, and it would be a contribution of mine.

Next week I will be abroad, and will probably not beeing able to do any work on. But anyway I am going to start with. It seems that there is some interest from other forum members. I intend to make it 'universal' perhaps up to you to add or modify some very specific functions.

Best regards.

[ceaser]

Hi Klaus & Dennishea

I am attaching a interface screen that is a bit modified. I have got rid of the toolbars and I have made use of panels and imagebuttons. I will add a small toolbar later to enable the user to select a layer that needs to be drawn on plus a small menu.

I will concentrate this week on the actual drawing routines and the snap options.

Something that also needs attention is the different coordinate systems. A normal cad will have it's minimum values (Y & X) in the top left corner and the maximum values in the bottom right corner. In the South African survey system, we have the minimum values (Y & X) in the top right corner and the maximum values in the left bottom corner.

Regards to all
Michael

[klaus]

Hi Michael & Dennishea,

In my mind a CAD system has the minimum X and Y values in the lower left corner, at least for what I have seen in 2D mechanical engineering CAD systems. That means already 3 systems (we are just missing the lower right corner).

How do you imagine the scaling, as I have seen, you use bitmap drawing and the resolution is one pixel. Depending on the displayx area scaling the resolution coud become relatively lerge.

And what about saving, bitmap or anything else ?

How will you handle the zoom ?

I have in mind to use vector graphics where we save the phisical coordinates and draw on a given display area with a scaling factor for the pixel. The accuracy is always maintained. The open question for me is the speed of the display refresh with a big number of elements (points, lines, surfaces).
I have begun a program, with a vector structure and will submit it as soon as there are some graphic functions working.

I think we should either open a new thread in the Open Source Projects directory or continue in Dennishea's Drawing program thread.

Best regards.

[dennishea]

Hi ceaser and klaus.

I think klaus is right about moving to another thread. The drawing program in open projects is fine by me, also I updated the zip file in my open source project. I added a table to start figuring how to save data. I don't have it any where near done but it is good enough for any one to say hey there's a better way. A little over a month ago my desktop died and I lost most of my work on this. I believe I have already said this once but I am not sure. That's what getting near your retirement age and prescription drugs do for you.